Remember that episode when Rose stops her dad from dying, and creates a paradox and those Reapers appear. Why did that happen in the first place? In the Eleventh Doctor episodes, we're always hearing about how "time can be rewritten", so why not that one?

Also, in the episode the Waters of Mars with the 10th Doctor, didn't the Doctor change time by saving all those people in the lab on Mars? If no paradox or Reapers emerged then, why did Rose changing saving her father result in such disastrous consequences?


4 Answers 4


Yes, Time can be rewritten & it happens in every episode of Doctor Who (even if you only time travel, you re-write the time). But, none of times, Time is Wounded.

Those Reapers appeared because time became vulnerable and it happened not because Rose saved her father. It happened because Rose saved her father in front of first appearance of Rose & The Doctor there. The first version of Rose & The Doctor weren't supposed to see another version of Rose.

In the same episode, Reapers became stronger after Rose touched her child-self. Its because time became more vulnerable after this.

The whole point is "Paradoxes attached with Time Traveler" wound the time. In Doctor Who, time traveler gets special attributes (remember how Dalek was able use Rose's genetic code to regenerate himself & he couldn't do this with other's genetic code).

Also, the effect of Time Wound wasn't just appearance of Reapers. Other effects were:

  • First version of Rose & The Doctor disappeared instead of running towards TARDIS.

  • Interior of TARDIS disappeared which was actually kicked out of wound.

  • "remember how Dalek was able use Rose's genetic code to regenerate himself & he couldn't do this with other's genetic code" - you are wrong the dalek was able to regenerate with any DNA but didnt want to b/c then he would change and be able to feel emotion, (which he actually does do, and ends up killing himself) he only uses her DNA b/c she says tat she doesnt fear him, (and since she does in fact fear him, he kills himself quote:'rose:"now what, what are you waiting for"dalek:"i feel your fear"'). Dec 1, 2013 at 2:30
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    @tryingToGetProgrammingStraight But, Dalek did say something like time travellers' DNA..
    – user931
    Dec 1, 2013 at 4:33

In "Father's Day", Rose asked specifically to be taken back in time to see her father on the day he died. The Doctor took her back, but she froze when the moment came upon her and failed to talk to her father before he died. She then asked if she could try again, and the Doctor obliged, but warned her that having two sets of themselves there at the same time made that moment a "weak point" in time. Acting on impulse, Rose ran out in front of her previous self and saved her father - not only negating her reason for wanting to go back in time in the first place, but also negating her reason for wanting to go back a second time and try again. It was a double-paradox, which severely damaged the time around them and attracted the Reapers. It was only once her father willingly ran out in front of the car that was meant to hit him that the paradoxes were undone and the Reapers fled.

In "The Waters of Mars", the Reapers don't even get a chance to show up because Adelaide killed herself and preserved the timeline with minimal changes before anything catastrophic could happen. As the moment that we saw in "The Waters of Mars" was explicitly denoted as being a fixed point in time, had it been left unrepaired it would have presumably had cataclysmic results just like the broken fixed point in "The Wedding of River Song".

When the Doctor says that "time can be rewritten," he is speaking generally - history can change depending on their own independent actions. However, it is when you attempt to change known history using pre-existing knowledge that only exists because of that history, or when you interrupt a fixed point in time, that you start to get into trouble.

  • but, surely, the doctor would have been aware of the reapers?
    – jim
    Aug 17, 2023 at 9:02

During the 10th and 11th Doctor, especially the 11th's run, there is some points in time that are fixed points. Meaning they have to take place, one such event was the 11th Doctor's death. If a fix point is changed, it damages time to the point that multiple events are happening on the same date without that date even changing. The second even stays the same. Now the Doctor did get around his 'death' while still allowing the event to actually happen (without spoiling it too much).

When they went back in time to see Rose's dad, it was a deliberate time travel event that was trigger by Rose wanting to see her father. It was a self conscious decision to be in that place at that time and that day. So deliberate that they went there twice. When Rose interfered during the second visit there, it caused the paradox as she removed the need to visit that period. It is why the first versions of themselves vanished, as the need to visit that point in the space/time continuum had gone.

Had the Time Lords still be around they could have corrected that damage preventing the Reapers from appearing. Thereby possibly avoiding that paradox.

While with Waters of Mars, it was more the TARDIS itself that sent the Doctor to that period in time. There was no conscious decision on the Doctor's part to be there.


It's a paradox because Rose was the one who saved him.

If her father didn't die she'd have no reason to want to go back to that day, thus there would be nobody to save him, meaning he would die. That is the paradox, and that is why he had to die.

In the waters of Mars, there was a similar situation in which the death of Adelaide Brooke was temporarily prevented. Adelaide on the other hand didn't have to die. She could have lived on and whilst it would have changed future events it would not have been a Paradox, thus there would be no Reapers.

The case where River refused to shoot the doctor was technically a Paradox as the River that had already shot the doctor was present. Technically there is no reason that the Reapers shouldn't have been present, but there are explanations as to why they might not have been present. One explanation is that the Doctor and River's lives have more of an impact on time (both being time travellers and time lords, and the Doctor's large impact on the world). Another explanation is that time did unravel in father's day and that the reapers were actually from a different time zone or planet (though that would mean the Doctor's explanation was a lie for some reason or another).

Another case was the big bang, in which the Doctor effectively got himself out of the Pandorica with knowledge he acquired from effectively nowhere. This demonstrates a key example of a paradox where an effect is also its own cause (the doctor knew how to get himself out because he had seen Rory doing it after the Doctor's future self informed him how). That had a different effect because by that point time was collapsing anyway.

In short, a paradox will always cause damage to time, but results can vary based on the situation. In Fathers Day the paradox was small enough for time to attempt fix itself

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    The paradox is still there - her stated reason for going back wasn't to save her dad from dying, but to save him from dying alone. She did that.
    – bdsl
    Aug 17, 2015 at 20:23
  • @bdsl Whether he died alone or not she'd still want to go back to save him.
    – Pharap
    Aug 17, 2015 at 23:00

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